Patent GB-1175789-A (GB)
Title: Disc Brake Assemblies
IPC: F16D55/227
Filed: 1968-07-18
Abstract: 1,175,789. Disc brakes. GENERAL MOTORS CORP. 18 July, 1968 [31 Aug., 1967], No. 34228/68. Heading F2E. The invention provides a disc brake assembly in which for slidably mounting a brake caliper housing 24, Fig. 1, at least one fixed mounting bolt, e.g. 18, is accommodated in a respective over-sized aperture 64, Fig. 4, in a portion 56 of the brake caliper housing 24 with the interposition of a resilient ring 80 which is maintained in a compressed state by engagement with an external surface 84 of the mounting bolt and also with a base 70 and side walls 74, 76 of a trapezium-section groove 72 provided in the portion 56, with the shorter parallel side 70 of the trapezium forming the base of the groove, the resilient ring 80 being thereby compressed sufficiently to prevent direct contact between housing and bolt in the region of the resilient ring under conditions of radial and axial loading of the brake caliper housing 24. As shown, the portion 56 takes the form of a flange, and four such flanges 56, 60 and 58, 62 associated with two mounting bolts 18, 20 are provided. The cross-section of Fig. 2 shows one brake shoe assembly 34 associated with the housing 24 and the other brake shoe assembly 30 associated with a piston 28. A brake disc 12 between them has friction surfaces 32, 36, and is secured to a wheel assembly 14 having a rim 100. During axial loading occasioned by application of the brake, small amounts of axial movement of the caliper housing are accommodated by elastic deformation of the ring 80, as shown in Fig. 4, where the flange 56 has moved to the right, whereas larger amounts of movement produce sliding of the resilient ring 80 along the mounting bolt. As shown, the resilient ring has a circular cross-section, but if the ring is of elliptical cross-section with the minor axis extending radially, there is less elastic deformation before the ring slides on the bolt surface, and therefore less retractive movement of the housing when the axial loading force is no longer exerted: pedal-travel is thereby reduced. The extent of radial loading imparted to rings 80 by application of the brake is limited by the construction now to be described. The housing 24 incorporates tie beams 42 and 44 (hardly shown), Fig. 1. When the disc 12 is rotating in the direction 46, Fig. 1, the backing plates 38, 40, Fig. 2, transmit braking torque reaction to the housing 24 through the tie beam 42, and this reaction is transmitted in turn by the tie beam 44 to a torque-receiving flange 50 forming part of a bracket 16, fixed to a non-rotatable -part of the vehicle, to which bracket the bolts 18, 20 are secured. When the disc 12 is rotating in the opposite direction a similar torquereceiving flange 48 is operative instead. Bolt arrangement.-Each bolt (e.g. 18) has a central threaded section 90 which engages a threaded opening 88 in the bracket 16. The ring 80 in flange 56 is in direct contact with a mounting section 78 of the bolt, while the ring in flange 60 is in contact with a spacer sleeve 98 located between the bolt head 96 and the bracket. When the bolt is tightened an elastic tension section of it, 94, is under tension.